In a tundish vessel of the type used in the iron and steel industry, there are typically variations in the purity of the molten iron or steel contained therein. When the molten iron and steel is in a nonagitated, nonturbulent state, impurities in the molten material tend to float to the top of the molten material, causing formation of a so-called "slag" layer. In other words, the purest of the molten iron or steel exists near the bottom of the vessel.
Molten iron or steel is poured into the tundish vessel from the top, and exits at the bottom. By maintaining a sufficient level or molten iron or steel in the vessel, and a sufficient residence time to allow impurities to float to the top, the concentration of impurities is reduced to a minimum in the lowermost portion of the vessel where the molten material leaves the vessel for further processing. Problems associated with impurities, occur, however, when the pouring of molten iron or steel into the tundish from the top creates sufficient agitation and turbulence that some of the slag material is forced downward into the lowermost portion of the tundish vessel, or is prevented from rising. Turbulence also occurs due to uneven and other undesirable flow patterns near the bottom of the vessel.
Various methods and devices have been invented for the purpose of reducing turbulence in a tundish vessel caused by the pouring of molten iron or steel into the vessel. In U.S. Pat. No. 4,177,855, a pair of swinging doors is shown in which helps protect the slag layer from turbulence caused by the pouring of molten metal. A flat impact pad provides an elevated splashing surface which helps contain the turbulence between the swinging doors.
U.S. Pat. No. 4,042,229 discloses an impact pad having a pair of sidewalls for inhibiting the flow of the molten iron or steel to the sidewalls of the tundish vessel. A second pair of sidewalls positioned far above the impact pad, helps separate the pouring region from the slag layer.
German patent 2,643,009 discloses a splash plate which includes a plurality of interlocking protrusions arranged in a honeycomb configuration.
Some of the prior art impact pads have facilitated the reduction of turbulence which causes impurities in the slag layer from becoming mixed with the molten iron or steel near the bottom of the vessel. Generally, these prior art devices have not facilitated the removal of impurities already present in the molten iron or steel when it enters the tundish vessels. In order to obtain the purest of molten steel from the tundish, attention must be given to removing already existing impurities as well as preventing impurities from being introduced into the product.